Glass charging and pressing apparatus and method



Nov. w, 1941.'

D. E. GRAY GLASS GHARGING AND PRESSING PPAHATUS AND METHOD Filed March 3, 1938 apparatus sive force as it tends to .position by the coldl mme Nov. 1s, 1941 v GLASS CHARGING AND PESSING APPARATUS AND METHOD Davia E. Gray, coming, N. Y., signor to coming Glass Works, Corning, N. Y., a corporation of New York 13 Claims.

The present' invention relates to methods and for pressing glass. In all past methods of pressing .glass articles with which applicant is familianin order to reduce the chill marks to a. minimum, the temperatureof the'mold is maintained as high as possible and still avoid sticking of the glass in the mold. In the vconventional methods of pressing, a Vgob of glass is introduced into a mold followed by a suitable shaping plunger. Ware pressed in this manner, however, is usually found' to, have chill marks in the region of the area in the mold first covered by the gob. These chill marks are caused by a l formationof a skin on -the edges of the gob next to the mold while the glass'is standing, just before pressing. During this time the skin becomes of such strength that when it is pressed down against the mold it moves in steps as compared with aperfectly smooth continuous rolling motion characteristic of skin free glass. These steps are due to breaking or localized bending of the4 skin which has become set up to such a degree that no amount of pressure will wholly eradicate them.

The effect upon the molds of. this method of pressing is to subject the central portion, or that part which is in contact with the glass the longest, to a wide range of temperature variations resulting in violent expansion and contraction without similaitreatments to the rest of the mold. The result is that this central portion is intermittently subjected to very great compresexpan but is held in Metal fatigue necessarily ensues rapidly.

Furthermore, because of the necessity of runv ning the molds at a high temperature the loss of heat from the glass to the mold is appreciably retarded and therefore the setting vup time is prolonged and the number of pieces of ware produced per mold in a given time is limited. Because of the metal fatigue of the mold, the total Application March 3, 1938, Serial No. 193,779

minimum of fatigue. thereby obtaining maximum mold life.

A further object is a 'method of pressing ware with thinner walls than 'permitted by past pressing methods, thereby reducing to a minimum the time for the glass to set up in a mold, and accordingly permitting the maximum number of pieces to be pressed per unit of time.

These objects are realized by pressing the glass in such a rapid manner that its final form is attained before the glass has given up any material portion of its heat or an appreciable skin has formed on its surface and holding the fully pressed article between the mold parts until the glass has become fully set up by transmission of its heat to the pressing surfaces.c By this method an article reaches final form before any part of the glass has had time to become set and, accordingly, no chill marks are formed. Also, since the charge of glass is spread out over the entire pressing surfaces before any appreciable heat is given up by the glass, such heat is uniformly distributed over the entire pressing surfacesand, accordingly, violent expansion and contraction of one mold surface area relative to another is avoided. Furthermore, since the glass Vreaches its final shape before giving up any appreciable amount of its heat a thinner article can y be pressed than by the conventional method,

portion which surrounds it.

number of pieces of ware, produced by a mold` before failure thereofis also limited. Also, because of the relatjlely slowvmotion of `theglass in the mold and the `rapid loss of heat, a large amount of glass is required to ll up the mold,

resulting in thick walled ware. f It is the primary object of the present invention to press glass articles in such a manner that ,f 'the chill marks, ordinarily resulting from too'f' long a contact `of` the gob with the mold prior lto pressing, are prevented.

`l'inother Objectis a method of pressing which subjectsFthe metal of the mold employed to a 'I'he invention embodies among its features a pair of mold elements supported and rapidly actuated bya system of cam actuated levers to seize a falling gob of glass and press it into 'a desired final shape; and of an electromagnet which holds the pressed articles between the mold elements for the period necessary to effect the desired setting up of the glass.

The preferred form of the invention is illustrated in the accompanying drawing in which:

Fig. 1 is a side elevation of the apparatus illustrating the mold elements in their fully open position d in receiving relation to a diagrammatically ustrated feeder; v Fig. 2 is avview of parts of Fig. 1,'illustrating their position just prior to seizing a falling gob; Fig. 3 is a viewsimilar to Fig. 1 but showing the mold elements as they have been brought to and l Fig. 4

being retained/in their closed position by the holding ma et. I

yIntheeni ent of lthe invention illustrated, 'l'l designates .a gob feeder which may be of any 'is a vr# similar, t Fig. a but with the cams slightly/advanced and the-mo1d elements conventional type properly timed to feed gobs of glass to the pressing apparatus as ,is the usual practice. Mold members I2 and I3 are mounted on the upper ends oi!- levers I4 and I5 pivoted on a. i'rame I3 atpoints I1 and I3. The lower ends of these levers carry rollers I9 and 20 constituting cam followers. The roller I9 is engaged by a cam 2I and the roller 20 by a cam 22. Both of these cams, are iixed to a shalt 23 intermittently rotated by an intermittent motion spur gear 24 driven by continuously rotating gear 25.

A connecting rod 26 connectslever I4 with a crosshead slide 21 which runs in suitable guideways 28 and 29. Mounted between slide 21 and the upper end of lever lli is a relatively heavy toggle 30 so arranged that, when mold members I2 and I3 have arrived at the final forming position, the toggle will be straight between slide 21 and the mold I3. ,Further upward movement of the toggle is positively prevented by an armature 3l, carried by the toggle, coming into engagement with the core of an electromagnet 32. Y

Considering the operating characteristics oi' the apparatus, it will be observed that the contour of cam 2| is such that the mold member I2 will be forced to v,travel through a large arc about pivot I1 at a rapidly accelerating speed, whereas the contour of cam 22 is such that the arc of travel and speedof acceleration'ofmold member I3 is relatively small, the main purpose of cam 22 being to limit the movement oi mold I3.to

the right while toggle I3 is in the folded position.'

The timing of the release of a gob of glass by the` feeder is such that the contacting of member I2 with the gob will occur when the mold member I2 has attained its full speed, which occurs a moment after the position illustrated in Fig. 2 is attained, the velocity of member I2 being ample t this. time to arrest the downward motion of the gob and to carry it on the face of mold member ,I2 intom ld member I3. Owing to the high speed at whic mold member `I2 and its driving lever I4 are traveling at this time, the associated connecting rod 26 also imparts a high speed of movement to slide 21 causing the toggle 30 to straighten up rapidly, its motion accelerating very rapidly especially as it approaches the straight line.l :For best results the Weight of toggle 30 must be such that its inertia will furnish great force as the mold members I2 and I3 approach their final position.

The period of dwell of the mold members in their Arlnal position is controlled by magnet 32 which becomes energized just before the mold members arrive at their final position and holds the toggle 30 in its straight line position until the glass has been properly set up.

As diagrammatically illustrated, the circuit for magnet 32 is under control of contact springs 33 actuated by a ca-m 34 on the surface of ,gear 25. cam is of such length that it holds springs 33 closed while gear 25 is rotating through an arc of approximately 100. The circuit for the magnet extends from terminal X of a suitable current source (not shown) through magnet 32, conductor 35 and contact springs 33 to the terminal Y of the same current source.

The circuit for magnet 33 is interrupted at -a as tooth 33 of gear 25 engages tooth 36. This period of dwell of the mold members in their maximum open position is utilized to permit the release of the nished ware from the mold members onto a suitable conveyor (not shown) before commencement of a subsequent molding cycle.

1. 'I'he method which includes seizing and pressing a falling charge of plastic glass into final form between pressing surfaces rapidly moving toward one another at different velocities.

2. A method which includes arresting the downward movement of a falling charge of glass by laterally moving it by one shaping element into engagement with another shaping element moving in the opposite direction to the iirst to shape the charge into a ilnished article and then holding the article to its finished shape between the two shaping elements until the glass becomes set.

3. The combination with means for releasing charges of glass from a parent supply body, of a glass pressing apparatus, including a mold assembly, a plunger assembly, levers interconnecting said assemblies, and means for simultaneously actuating said levers to move said assemblies toward one another in directions transverse to the direction of movement of a Vreleased charge and to move at least. one oi said assemblies over a path intercepting that 'of the charge.

4. In a glass press, two levers each pivoted invterrnediateits ends and each having a pressing fmember supported' on one. end thereof, means cooperative with the other end of one of said levers to move its pressing member about a relativelyfshort arc towards the other pressing member, means cooperative with the corresponding end of the other lever to move its member about a comparatively long arc toward the other pressing member and until said pressing members meet. 1 l 5. In a glass press, two levers each pivoted intermediate its ends andV each having a pressing member supportedi on one end thereof, meanscooperative with the other end of one of said levers to move its pressing member about a relatively short arc towardsthe other pressing member, and means cooperative with the corresponding end of the other lever to move its member about a comparatively long arc toward the other pressing member and until said pressing members meet, a slide member, a folded linkage between one of said levers and said slide member adapted when fully unfolded to hold said pressing members in meeting relation, and a rigid linkage between said slide members and the other of said members for moving said slide ,member during the movement of said members'towards one another as required to fully unfold said first linkage coincident with the meeting of said members.

6. In a pressing assembly, two pressing units arranged to move toward one another into pressing relation, means for moving the i'lrst unit over a relatively long path toward the second at a rapidly accelerating speed, and means for moving the second unit over a relatively short path toward the first unit at a lesser accelerating speed.

time that cams 2I and 22`a're fn a position to permit the toggle to drop to the position illustrated in Fig. 1, thereby effecting,v the full opening of the mold members. At this time the teeth 36 and 31 of gears 24 and 25 are about to mesh and f accordingly the mold members remain fully open until commencement of their closure is started 7. The method of forming glassware, which includes severing a mold charge from a parent bodylof molten glass, engaging one side of the mold charge with a mold member as the charge leaves the parent body, moving the mold charge in an arcuate path which intersects its initial path of movement and engaging the opposite side of the mold charge near the end of its arcuate y movement with a mold member to press the charge intothe desired shape.

8. The method of pressing glassware.vwhich includes severing a mold charge suspended from a parent body'of molten glass, moving the mold charge transversely of its initial direction of movement as it leaves its point of severance, halting the transverse movement of the charge and pressing it into the desired shape while such transverse movement is being brought to a halt.

9. Themethod which includes intercepting and halting the fall of a charge of glass substantially immediately after its severance from a parent' supply body by striking it a blow with a shaping surface moving in a direction transverse to itsy i pended charge of plastic 'glass from a parent body, thereafter striking and in part shaping the freed charge by a moving shaping surface before movement of the charge as a whole ceases and of completing the shaping of the charge into a finished article by subjecting it to the action of another moving shaping surface also before movement of the charge as a whole ceases.

12. The method which includes freeing a descending charge of plastic glass from a parent supply body, intercepting and changing the direction of movement of the charge by a rapidly moving shaping surface, and halting the movement of the charge by its engagement with a second shaping surface moving toward the charge.

13. The combination with means for releasing charges of glass vfrom a parent supply body, of a glass pressing apparatus including a pair of arms each supporting a pressing unit, and means for simultaneously actuating said arms to move their pressing units toward one another in directions transverse to the direction of movement of a released charge and tomove at least one of said units over a path intercepting that of the charge.

DAVID E. GRAY. 

